The present invention relates to a method for checking a value document and a corresponding checking device.
Value documents are understood to be sheet-shaped objects that represent for example a monetary value or an authorization and hence should not be producible arbitrarily by unauthorized persons. Hence, they have features that are not easily produced, in particular copied, whose presence is an indication of authenticity, i.e. production by an authorized body. Important examples of such value documents are chip cards, coupons, vouchers, checks and in particular banknotes. The value documents can differ respectively with regard to their type, for example in the case of banknotes with regard to their denomination or the nominal value and the currency or in the case of checks with regard to a type of check form determined by the issuer of the check.
Torn or torn-apart value documents are frequently “repaired” with the aid of adhesive strips. The value documents provided with adhesive strips are to be recognized and sorted out upon the checking of the value documents. In the methods so far for recognizing adhesive strips, the thickness of the value documents is checked. However, the detection of adhesive strips is impaired by variations of the detected thickness measuring values. When the adhesive strip is very thin in addition and/or the value document itself already has a pronounced thickness profile, the hitherto recognition of adhesive strips is limited.